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Stability and Bifurcation in Reinforced Boreholes

  • Euripides PapamichosEmail author
Conference paper
  • 1.6k Downloads
Part of the Springer Series in Geomechanics and Geoengineering book series (SSGG)

Abstract

Rock nailing of a borehole is considered as a means to reinforce the rock and increase its borehole failure strength. The technique is modeled using Cox’s original shear-lag method. In the continuum sense, nail reinforcement is viewed as a body force that acts as a confinement. The finite element formulation of the reinforced elastoplastic borehole is presented and results from an elastic analysis with stiff nails are compared against existing analytical solutions for elastic rocks with rigid nails. The formulation couples the mechanical behavior of the rock with the nail-rock contact law equation that have to be solved in a coupled manner. The bifurcation condition for borehole failure in a Cosserat elastoplastic rock is subsequently extended to a reinforced borehole for stability analysis.

Keywords

Bifurcation Condition Borehole Stability Finite Element Method Formulation Strain Increment Vector Elastoplastic Constitutive Relation 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgments

This work has been performed as a part of the research project “Formation reinforcement for wellbore stability and sand control” funded by the PETROMAKS programme of the Research Council of Norway and BP Norway (Project number 215667/E30).

References

  1. Cox HL (1952) The elasticity and strength of paper and other fibrous materials. Br J Appl Phys 3:72CrossRefGoogle Scholar
  2. Papamichos E (2010) Analysis of borehole failure modes and pore pressure effects. Comput Geotech 37(1–2):141–152CrossRefGoogle Scholar
  3. Papamichos E (2011) Stability of nail reinforced wellbores. In: Bonelli S et al (ed) Advances in bifurcation and degradation in geomaterials. Proceedings of the 9th international workshop on bifurcation and degradation in geomechanics. Springer, Porquerolles, France, pp 93–99Google Scholar
  4. Papamichos E, Vardoulakis I (2012) Rock nail reinforcement of a free surface. Int J Numer Anal Meth Geomech 36(2):203–218CrossRefGoogle Scholar

Copyright information

© Springer International Publishing Switzerland 2015

Authors and Affiliations

  1. 1.Department of Civil EngineeringAristotle University of ThessalonikiThessalonikiGreece
  2. 2.SINTEF Petroleum ResearchTrondheimNorway

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